Level 5 there's nothing that will really destroy a campaign.
Diplomancer. 53 diplomacy on take a 10 before a magic item of +x to diplomacy.
[spoiler]
8 from skill ranks
8 from item familiar (you'll want 16 int and a 6 skill point class).
5 from CHA (16 points for 18 CHA +2 from half-elf paragon, 10 points for 16 INT)
10 from take ten
2 half-elf
6 synergy
9 feats (negotiator, skill focus, nymphs kiss, sacred vow)
2 traits
1 half-elf paragon
[/spoiler]
with a +7 skill item (which can also act as your item familiar) you hit 60 (AKA everyone who can hear me becomes my very good friend in 6 seconds).